This invention relates to fixed spray sprinklers having a flow shut off valve.
Fixed spray sprinklers are well known which comprise a fixed spray nozzle that is threaded onto the top of a flow conduit. Both the nozzle and the conduit are considered “fixed” because they do not rotate about their axes during operation of the sprinkler. The nozzle might be adjustable to vary the spray. However, once the nozzle is initially adjusted to provide a particular spray, that spray covers a particular area of the ground without rotating or moving the spray relative to the ground.
Typically, fixed spray sprinklers are sold without pre-installed nozzles. A flush cap used on the top of the flow conduit in place of a nozzle. The flush cap is used for flushing out dirt and debris from supply lines. Once the sprinkler is installed but before the flush cap is removed, the sprinkler system is pressurized for the first time. The flush cap is designed to let water exit through the cap during this initial pressurization to flush out any debris that may have gotten inside the supply lines. After this initial flush, the flush caps are removed and replaced with nozzles.
FIG. 1 illustrates a conventional pop-up sprinkler device 10 on which a flush cap 12 is installed. The flush cap 12 is attached to an upper end of an inner conduit 14. The inner conduit 14 moves telescopically within a housing conduit 16. The inner conduit 14 and the housing conduit 16 are coaxial. A metal retraction spring 18 holds the inner conduit 14 in a retracted position within the housing conduit 16 when the water supply to the sprinkler device 10 is off. The spring is located between the inner conduit 14 and the housing conduit 18 and is coaxial to the inner conduit 14 and the housing conduit 18. A cap 110 is threaded to an upper end of the housing conduit 16. The cap 110 has a central opening to permit extension of the inner conduit 14. The cap includes a seal member that, among other things, forms a seal against the inner conduit 14. The upper end of the spring 18 engages the cap 110, which provides a fixed surface. The lower end of the spring 18 engages a spring retainer 112, which is axially movable and is fitted to the lower end of the inner conduit 14.
FIG. 2 shows the sprinkler device 10 when a nozzle 22 and filter 24 are installed in place of the flush cap 12. As shown in FIG. 2, the upper end of the housing conduit is located approximately at the ground level. Thus, parts of the sprinkler device 10 that extend above the ground level are subject to damage from lawnmowers, vehicles, vandalism and the like. FIG. 2 includes a dashed line, which indicates the surface of the ground in which the sprinkler device 10 is buried.
When pressurized water enters an inlet 114, water pressure acts against parts such as the inner conduit 14 and nozzle 22 to compress the spring 18 and to extend the inner conduit 14 to the elevated spray position shown in FIG. 2. When the water supply to the inlet 114 is shut off, the inner conduit 14 is retracted by the restoration force of the spring 18, and the nozzle 22 returns to a position such that very little of the nozzle 22 extends above the cap 110. If the inner conduit 14 is broken or ruptured when water pressure is supplied to the inlet 114, there is nothing to stop water from flowing from the inner conduit 14. Thus such damage can waste water and cause flooding.
U.S. Pat. No. 4,562,962 to Hartman discloses a fixed spray sprinkler equipped with a flow shut off valve. The flow shut off valve includes a poppet valve that is normally held open. If the sprinkler nozzle is broken or removed, the valve closes to prevent water from flowing out through the flow conduit. The valve is located adjacent the bottom of the flow conduit. However, the sprinkler of U.S. Pat. No. 4,562,962 does not retract and is thus subject to damage. Further, there is no indication that the shut off valve of U.S. Pat. No. 4,562,962 functions with a flush cap.
U.S. Pat. No. 6,179,221 to Goldberg et al. discloses a fixed spray sprinkler equipped with a flow shut off valve. However, the shut off valve is relatively high in the flow conduit. Therefore, if the flow conduit is cut or broken at a point at or below the shut off valve, water will flow from the conduit, and the shut off valve will not function.